Two dimensional tests of GA(W)-1 and GA(W)-2 airfoils at ...ABSTRACT Tests of the GA(W) -l and...
Transcript of Two dimensional tests of GA(W)-1 and GA(W)-2 airfoils at ...ABSTRACT Tests of the GA(W) -l and...
Wichita State University Libraries
SOAR: Shocker Open Access Repository
Wind Energy Reports, no.1 Center for Energy Studies
Two Dimensional Tests of GA(W)-1 and GA(W)-2 Airfoils at Angles- of-Attack from 0 to 360 Degrees
Dale Satran and M.H. Snyder Wichita State University
Recommended citation Dale Satran and M.H. Snyder. Two Dimensional Tests of GA(W)-1 and GA(W)-2 Airfoils at Angles- of-Attack from 0 to 360 Degrees. Wichita, Kan: Wichita State University, 1977. -- 37 p. Digitized by University Libraries and posted in Shocker Open Access Repository
Citable Link: http://soar.wichita.edu/dspace/handle/10057/5692
Terms of use: in the Public Domain
WER-l
P6-IZ-06-0(l
Wind Energy Report No. 1
TWO-DIMENSIONAL TESTS OF GA(W) -l
AND GA(W) -2 AIRFOILS AT ANGLES - OF-ATTACK
FROM 0 TO 360 DEGREES
by
Dale Satran
and
Melvin H. Snyder
Wind Energy Laboratory
Wichita State University
Wichita, Kansas
January, 1977
FOR EARLY DOMESTIC DISSEMINATION
Because of its s'ignificant early commercial potential, this information, which has been developed under a State of Kansas program using NASA information, is being disseminated within the United States in advance of general publication. This information may be duplicated and used by the recipient with the express limitation that it not be published. Release of this information to other domestic parties by the recipient shall be made subject to these limitations. Foreign release may be made only with prior NASA approval and appropriate export licenses. This legend shall be marked on any reproduction of this information in whole or in part. Date for general release: January. 1979
ABSTRACT
Tests of the GA(W) - l and GA(W)-2 airfoil s were conducted in the 2- D test section o f the Wichita State University 7' x 10' low speed wind tunnel to de te rmine the lift , drag, and pitching moment coefficients of the airfoils. The chords of the aluminum models were six inches. Thg airfoils ~ere tested a6 three Reynolds numbers: .37 x 10 I .51 x 1 0 , and .67 x 10 , and at angles of attack from a to 360 degrees . Hysteresis studies were also performed from negative stall to posi tive stall .
INTRODUCTION
As a part of the continuing wind energy re s earch program at Wichita State University, a two- bladed wind turbine was designed and built (re ference 1). It became evident, during the design process and during the calculation of off-design performa nce, that there is a serious lack of airfoil data for low Reynolds numbers a nd for large ranges of angle of attack .
From the limited data availabl e , it appeared that the GA(W)-l airfoil would be a better section for a windmil l blade (i.e., shorter chord and lighter weight) than the o l der sections. For this reason, the wind turbine , described in reference I, was constructed using a GA(W)-l airfoil.
In order to provide desi g n data for future wind turbine designs, tests have been conducted in the Walte r H. Beech Wind Tunnel at Wichita State University . These tests, reported in this report, were two-dimensional te s ts of the GA(W)-l and GA(W)-2 airfoils .
MODELS AND TEST PARAMETERS
The models tested were the GA(\'l)-l and GA(\v) - 2 airfoils. The contours and surface coordinates of the GA(W)-l airfoil are shown in figure 1. Figure 2 illustrates the GA(W) - 2 airfoil , but the coordinates have not been released for general publication. Persons desiring these coordinates must apply to NASA. The models were constructed of aluminum with sixinch chords.
The standard 2-D tunnel walls are 3 feet aRart, and usually the models have- ·for:ty-two-inch diameter end plates_ (for models with c = 2 ft.) . . These 6-inch chord models were equipped with l2-inctldiameterend plates an~the angle of attack drive was modified to permit testing through an angle of attack range of 360 degrees. See figure 3.
The Reynolds numbers attained were fixed by t he limits to the dynamic pressure. Minimum dynamic pressure, fixed by repeatability of data, was 8 psf. and corresponded to Reynolds number of about 350,000. Maximum dynamic pressure was limited ~_ bending ~ of ..-the mQgel which produced deflections of the end plates. For these small models, ~y'namic pressure was limited to 48 pst. corresponding to a Reynolds-' fiumber of approximately 7·0-0,000.
TESTING
The models were tested for a full 360 0 and were tested for hysteresis by rotating the airfoil from deep negative
1
stall t o deep positive stall and back to deep negative stall. The models were tested at three dynamic pressures, 8 , 18 and 4 8 psf . These data were taken o n t h e force b a lance. Wake s urveys were also performed using a five-tube probe to measu re the total pressure variation through the wake (see fiqure 4).
DATA REDUCTI ON
Force data were reduced by a comput er program whi ch corrected the data for f l ow angularity, solid blockage , wake blockage, horizontal buoyancy, and turbulence as shown in the Appe ndix. The' program (refe rence 2) computed lift , drag , pitching moment about the quar ter chord , normal and axial coefficients for each angle of attack. Drag data from the force balance included interference and tare d r ag for the end plates . The dif ferences between the drag data from the force balance and from the wake survey were removed by the p r og r a m f or each model to yield the actual drag of the model.
Pressure data from the f i ve-tube wake survey p r o be were "reduced into ve l oci ties whi ch were integrated by another p rogram to yield drag of the model only . The wake survey was taken too far (six inches) behind the model. Velocity p rofiles through the wake were very flat wh ich hindered determination of the wake boundaries. By changing the integration limi ts by on ly one pe r cent , the drag could change as much as fifty to one h undred pe rcent . By determining the best range of d r ag f or the wake sur veys at each angle of attack and by plotting a curve through the average of these drag values, a table of the d rag coefficients was gene r a t ed for each air foil. Minimum drag coeffic i ents are compared , in figure 5 , wi th ski n f ricti on coefficients for all-laminar and all- turbule nt flow.
Wake da t a were used t o correct the drag when the airfoil was not stalled. When the airfoil was stalled , interference and t are drag we r e considered c onstant and were subtracted from the force data.
RESULTS
Corrected aerodynamic characteristics of the are presented graphically in figures 6 throug h 8 . results are presented in tables I and II.
2
airfoils Principal
REFERENCES
1. Dunn, C.H., and Snyder, M.H.: "A Prototype wind Generator Sys tem Supplying Energy to the Electric Utility Grid," University of Missouri-Rolla Energy Conference , Rolla, MO, Octobe r 1975.
2. Rotramel, Breiden thal, and Wentz; Computing Routines for Airfoil Section Wind Tunnel Data Reduction , Aer onautical Engineering Department, Wichita State Univers ity, June 1973.
3 . Wentz, W.H.,Jr., a nd Seetharam, H.C.; A Fowler Flap System for a High-Performance General Aviation Airfoil, Paper no. 740365, S.A.E. Business Aircraft Meeting, Wichita, Kansas, April 1974.
3
SYMBOLS
b airfoil span, d i stance between end plates ft.
C airfoil chord ft.
Cd section drag coefficient, D/qbc
c l section l i ft coefficient, L/qbc
c rnc section pitching moment coefficient, Mi-/qbC 2
T
o drag lb.
L lift lb .
pitching moment about the quarter-chord ft.-lb.
q d · 1 v2 ynam~c pressure, 2P p . s. f.
RN Reynolds number, pVc/v
S wing area = be sq . ft.
t maximum thickness of airfoil ft.
v wind tunne l velocity ft . /sec.
a angle of a t tack. deg.-
coefficient of viscosity slugs/ft. sec .
air density s l ugs/cu. ft.
4
TABLE I
Pr incipa l Parameters fo r GA(W) - l Airfoil
Reynolds Number . 37 x 106 .51 x 1 0 6 .67 x 1 0 6
c l = 0.0 at a = -4.2 ° - 4.3° -4.4°
a = 0.0 at c l = .47 .50 .52
clmax = 1. 35 1. 39 1. 43
.0/10
Cdmin = ~ge_ .0 102 . 0077
L/Dmax = 66.69 76 . 16 86 . 27
at
a = 6.20 6 .20 2.20
Stall + a 16.2° 16. 2° 16.2 °
Range - a - 11.8° - 11.8 0 - 11.8°
5
TABLE II
Principal Parameters for GA(W)- 2 Airfoil
Reynolds Number .37 x 10 6 . . 51 x 10 6 .67 x 106
c 1 ~ 0.0 at a ~ - 4.6° _4.7° _ 4.8°
a ~ 0.0 at c 1 ~ .50 .52 . 54
Clmax ~ 1. 37 1. 42 1. 45
Cdmin ~ . 0122 . 0091 .0067
L/Dmax ~ 66.65 84.44 87.64
at
a ~ 4.20 4.2° 4.2 0
Stall + a 12 . 2° 14.2° 14 . 2°
Range - a - 11 . 8' - 9.8° -9.8°
6
chord line
tic ~ 0 .17
GA(WH Airfoil Coo!dinales
Uppe! SUlface Lower Surface:
XI' ~ XI, ~
0.00000 0.00000 0.00000 0.00000 0.00200 0.01300 0.00200 -0.00930 0.00500 0.02040 0.00500 - 0.01380 0.012,50 0.03070 0.01 250 -0.02050 0.02500 0.041 70 0 .02500 • -0. 02690 0.03750 0 .04965 0.03750 -0.03 190 0.05000 0.05589 0.05000 - 0.03580 0.07500 O.06SSI 0.07500 - 0.()4210 0.1 0000 0.07300 o.looon · 0.04700 0.12500 0 .07900 0 .12500 - 0.05 100 0.15000 0.08400 0.15000 -0.054)0 0.17500 0 .08840 0.17500 -0.05700 0 .20000 0 .09 20!'! 0 .20000 - 0.05930 0.25000 0 .09770 0 .25000 - 0.06270 0.30000 0.10160 0 .30000 -0.06450 0.35000 0 .10400 0 .35000 - 0. 06520 0.40000 0.10491 0.40000 - 0.06490 0.45000 0.10445 0 .45 000 -0. 06350 0.50000 0.10258 0 .50000 -0.06100 0.55000 0.099 10 0.55000 -0.05700 0 .57500 0.09668 0.51500 - 0.05400 0.60000 0.09371 0.60000 -0.05080 0.62500 0.09006 0 .62500 -0.04690 0.65000 0.08599 0.65000 -0.04280 0.67500 0 .08136 0 .67 500 -0.03840 0.10000 0.01634 0.10000 -0.03400 0.72500 0 .07092 0.72500 - 0.02940 0.75000 0 .065 13 0.75000 -0.02490 0.17500 0.05901 0.17500 -0.02040 0.80000 0.05286 0.80000 -0.01 600 0.82500 0.04646 0 .82500 -0.01200 0.85000 0.03988 0.&5000 - 0.00860 0.87500 0.03315 0 .87500 -0.00580 0.!l/0000 0.026)9 0.90000 -0.00360 0.92500 0.0 1961 0.92500 -0.00250 0.95000 0.01287 0.95000 - 0.00260 0.91500 0.00609 0.91500 -0.00400 1.00000 -0.00070 1.00000 -0.00800
Fig ure 1. GA{W) - l Airfoil.
B
chord line
Figure 2. GA(W)-2 Ai rfo il.
9
Figure 3. View Of 2-D Test Section From Downstream Of Model .
Figure 4. Wake survey Probe In Position,
Viewed From Downstream Of The Model.
·014
.0 12 o
. . 010
.008
.006
.004
o
e> GA(W)-l
Cl GA(W)-2
_ All turbulent C, flat plate
o
o
All laminar flat plate
0L+~ ____ -+ __ -4 __ ~-+-4-+~r+c-___ 10 5 10
6
Reynolds Number
Figure 5. Airfoil Minimum Drag Coefficients.
"
-, . --f--·'!--:-·---~::---·
- .. ,-----'--- -
. "
" I -I " ."_ ...
, - :'--rl '-~ --,
-,r.: -'~ ":":: '-j ~:-+-': ; . .. _-",' . , : .I -·f 1' " " '
:""+';-}-·'cl . -;-:..:.:...._._. -- . :-.- ., 1· . : +'--~r---r-- ,;:-" '; ", j " +-h+". --i -+':-'--l-+-'--;---',-';++- •• ~"
;2~"~,~i:~~Sj~i~:;:~r.'~~T~C 4~:~',,~~=~E~~~~~~] - ;--- .,~. -- ~-.~-- _ .. -.- - -- '-; - T-: - , ! I
_-_.-I_:.; :.'-._ .. ll.·:~.:_.·-);: ·· . .-'.-_·.l.;.~' .• --- ",-:.- :. _:i,-:. ro
" r i,.
- .4 - -:+ -r: !- ~ -) -: .~';~:--" -.-, . . ' I " - ~~-''"'''r ;-"'i ".-__ . __ _ ' __ _____ .. ~. ___ ' ___ ~ _ . .. __ L..-......i C:'~r:-- -T--·-- --··~ . -------".·1 -+.,-...
.' , . • -I ,. . .. -.--'--
i , ::.~~.~_-~~ ~ ·t::-: J. ' - -,'- -- -,,_. ------...- -.-,""'-' - ----- - ---.
--1" " , •• _1
, .. _. ,- -- - - ---' . -
.os
- ,05
-.15
-_20
, . GA(W) -2 AIRFOIL SECTlON~ij~Eijj~~
Wichita State University :::
__ L
I. .. _-_ • . j
I '-_ .. _1
i "-, ... ~
4 -1_ - - - .---.--. ac
o o
2-D Test madel clean
RN .51 x io6
increasing
,
_._ ... ,-- ------_. ~ -
,-+ -,._-----'--------
16 20 degrees
"'-- .," _. - ,' ,-' .! ..
. , .. '! . .
, ,
FI GURE 80
,.
-; .. -::;- '--'--._ .. _.-..
, ,. .,
-:-, ._--- .'---_. ,.
, , 1-'-'--- :--. , . .
._------- :--; . :;; : . . ' , . :- T.-~'-T: '"-- . I '-! .. _-" .. ---,. _.... .... ..
+- ·1-"'--;-·- -;.- .. ... +:: :.~-~.:t:~-:!~~~:-~ .,.--;--+~ .:._ 1_ -,.. ..
: J _~.~ . u~.- ~ "-J~!:I' rCL~-~ P . . , .
-.. ----_ . . - ·---;----·-f .. ----I. I ,, : ;.' . ~; ! -~·~t_:~_l.,~-~;~~~~-.· r
_',----C_
._ .. ;_..:...._l .. ~ __ . __ . ._:...j....:i~_.:, .. _~ __ .i ___ --'-_ J
-.15
-.25·
GA(W) -2 AIRFOIL SECTION Wichita Sla te
2-D University
Test model clean
RN
..~--'-
{; Increasing Ot. I'-'~ _._- --:-'---:-
'V ._. Ot. ,
12
!-. -. r·· ,.-
, . ,-
+-, . . + --- -,---~ .. -.----....:.. , .
-r T r-,:~.- r .. :' ; -·-·-I---;----·-- o--.. --~~:~,· ~:-c_+-'-'.~~~~~~,i~kJ~
.~.,-.. ___ ._: _' _ ._ ;~, .• " __ c_,_ ... _" __ •. "_
-~- - - - -'--. -- - ;-_. -,-,-, , ---- -.. _---- ---
AIRFOil SECTION State University 2-0 Test
niode"' dea n RN
;51 x i06 o increasing oc.
detreasil'!9
"
AIRFOIL ~~r'TlI"l,N State University
'2-D Test model ,lean
RN
.67xl06
6 increo5ing oc, .
>--~ ... " . , ,,,-,,,,, I ;.;.;.] ,_'-._ , • • • • ,-' ... . _ _ ,.o . ...... ;..y " .... • . • • _. , _ . • • ' • •• • , • • ,.
-I' ~ C g _.- - 0 OCIhG,l -0 ~ => ~ u z .g ";; -:::; ... -, . ... ~ ,,;..;.. ... --.. .--.. ;...;..... - -""., ........... ........... -... . -!OC;o:: )( c '<0 1 '0 ..... Q)
~C'& .O M ti N E •• 5 I 0 - " __ ,'" j "+" M'-"" 'j'''''' ' j"+ c,'' h'T't.,..;',~ , .. ~~.'.,.-",~-.• ,". :!: 1.:. I', . l . 1 \ ;d ' _ , ;\ .:V . I . I. I - .: I . :,
.s: 0 V
. , . , ., ,... c.J . ,. , I " , ;: ;C 'Ct' r , ' t:":'!f'" "1' tel ' j";C"''''l''T,j j'" T" ; . ';~ 'I' I' I ", ~"""-'-"""IC"C ' . ,"~ . ' '- ' r"-' [ '-'1,,-'1'-:;": , .... ' 1-;" -c .-r-l---"i-'·", """ o • I . ' I : - . : , :' i .1 I ; , •• I ." ! : ; , i : '.. , ' • ~ , I ! ' . I I ~. ~: I . I ! I L ,
- i· ". , , I _j
I ' " ~ " J " " j , , " , I q J f ·' L!~ , J L~ __ ,. L ' !- ., j .' .
t ::. ' k" - - - - .--.- -.- - ... .• - .. :
"" .. ,
-:,
"''''
,hi.J .c): 't:' . ..! . {CFc.HF!L.!o.~;.HI;C~·.--!.c~'H,,:t; J ~ :·':Lf ''''''1'' '1'' 'I ' -i. '·lu e:'L i l'c'~:;',_~L ;L -r", l~" . . _ _ .. . I ~ _ .1. .", ' __ ':i\ .• .. 1. •• : •
,. .". l:
"', .,-".,.,.,
,. o
!
I
.0 .-
:.. i
o
I . I .
I
! .! '--r'
!. 0
I I
4
GA(Wl-l AIRFOIL SECTION WI CHITA STATE UNI VERSITY
2-D TEST ;~~JEB~~~ REYNOLDS No, ·,67x I0· Cc.
A INCREASI NG ex. . =~FEfr~tt~liillll 'iJ DECREAS I NG ex ,~
'.
,. o.
, ,. .1.
8 deg
GACWl-2 AIRFOIL SECTION WICHITA STATE UNIVERSI TY
., i , , .
2-D TEST f:'l!~§liill REYNOLDS No. _.37x IO· ,. .. o INCREAS ING ex. II DECREASING ex
I
.i
, . ,
I , , ,
. ,. I , . I ' .. .
, ," i' ,
" ~ ,. . I
.' ,. ,. .i . :
8 o '"
12 , (
L ,I , , !.
1
+ :1 'C I , , d
i ,
:l , I , ,
" ! I "
! I "
" I. :1 .! ., I, ,I
"
,
I ,
" ,
, , "
" ! "
I, ;.
i
.
· 1-
·i
'. ! .1
"
.,
,
6A(W)-2 AIRFOIL SECTI ON WICHITA STATE UNI VERS ITY
2-D TEST REYNO LDS . No. =.5"/ x /O'
0 INCREAS i NG ex. <> DECREAS ING ex.
'! ,
., : j , "
, ,
, ,
OC
., "
GA(Wl-2 AIRFOIL SECTION W1CHlTA STATE UNIVERSITY
2-D TEST REYNOLDS No, • ,67>/0'
'" IN CREASING ex '<;J DECREAS ING ex
... ~ - : , --
"0 'j
I' ,
"! ., . .. :
I, I .. , . . i I
i i
,.
I " L ,
.. " .. ,
.,
l~r" . A(WH AIRFOIL SECT ION ~ -F-~[+L .~~.+:: '. .: '0, ':, f'C; r I ,:, . , ", I :"::': ·
Cf4 .. W, CH,TA STATE UNI VERSITY : .:LI"'; ·' .' ••. _ .. ':' :.' .:-- i . '. :
2-D TEST " . . " ., ." l ,.: ..: ' . • 8 REYNOLDS HUMBER : : . ,I.,,;: , ... V . '. ",-;
. . 0 0. 37 x 10: hi:::;:-; ' ,H -rT',jf+-; . i , . ...
. .' 00,51 x 10 '. ' ~-;- _<;) .0 .. !" . '.' ,C, ,."_',e,· ; .6 i.1 _"~ ~ O,67 x 10' i : • ·.J.··Y· .a ; a: '" .'. r. . 'E!" ,
d~.:. , . " 1' :;:, ;-::- i tl ,,( 8 . . • ' i;<' . "'! ' .' .
;.')"" .-:-~-~ ,.. :., '1-:' . . -..; .,.: AIRFOIL SECTION
GA(Wl-l AIRFOIL SECTION WICHITA STAT E UNI VERSITY
2-D TEST • REYNOLDS No. ·.37. 10
o INCREASING ex. Q DECREASING ex . . . , .
~ . .
GA(W)-2 AIRFO IL SECTION WICH ITA STATE UNIVERSITY
2-D TEST REYNOLDS ;10, • .3 7 • /0'
INCREASiNG .ex le"· 'i -'-F~i-·:
,
I ;. , ,
4 8
, i .. I I
1 .I
I I 1
I '
12 16 deare;i'
AIRFOIL SECTI ON WICHITA STATE UNIVERSITY
2-D TEST REYN OLOS Ne. =.51-10'
o INCREASING ex. o DECREAS 1 NG ex
4 ex
!
i "
.!
!. !
6A(W)-2 AIRFOIL SECTION WICHITA STATE- UNiVERSITY
2-D TEST ~EY.OLDS No. -.67x 10'
6 INCREASING ex ~ DECREASING ()(
I
, .. ' I "
.. !
1.4 '
i , .
·1.
40 80 120 t60 200 degrees
.. '.
24Q 280
6A(W)-l AIRFOIL SECT ION WICHITA STATE UNIVERS ITY
2-D TEST REYNOLDS NUMBER
00.51 x 10'
60.67 x 10'
,
, , , ,
,!
"
, , , ' ,
" ,;
"
"' ,
240
'! : , ,
2.0
-----~'-----'--". - ,
WICHITA STATE UNI VERSITY
, .' "
320
2-D TEST
REYNOLDS NUMB ER
o 0,37 X 10'
o 0.51 X 10'
t:. 0,67 X 10'
"
GA(Wl-l AIRFOIL SECTION WICHITA STATE UNIVERSITY
2-D TEST ReYNOLDS No. • . 37·/0
C INCREASING
Q DECREAS I NG
B 12
0:-
ex
• , .,
,1 .
. . i.
.1 : ,
.. .. ,' i GA<W>-l AIRfOIL SECTION WICHITA STATE UN IVERS ITY
2-D TEST .. REYNOLDS No . =.5/ - /0' ..
0 JNCREASING (X. !
0 DECREASING ex ::.j .
• !- .,~.;,
I
! .. ! ., • I ..
• .. .II . :,
I .. i '
I . .. .. ! I , • t,' , .. . I:
, o. j I ,
• ..
, !
I' .
. I'
t· • I .. ,: . ,
;. -12 -8 0 at 8 12
I
1.0 .
I I '1
1.5
.5
,.
,
i
.L
GA(Wl-2 AIRFOIL SECTION WICHITA STATE UNIVERSITY
2-D TEST REYNOLDS NU~ER
o 0.37 X 106
o 0.51 X 106
6 0.67 X 106
. 1
I , ,
'-i
GA(Wl-l AIRFOIL SECTION WICHITA STATE UNIVERSITY
2-D TEST'
REYNOLOS No. ·;37 x/O' INCREASING ex.
GACWl-l AIRFOIL SECTION WICHITA STATE UNIVERSITY
2-D TEST • REvNoLes No • • • 5/ -/0
o ex. <> ex
~ji" -1
. r
GA(Wl-l AIRfOIL SECTION WICHITA STATE UNIVERSITY
2-D TEST . 6
REYNOLDS No. - .67-/0 6 INCREASING ex.
CJ(
I